{ "id": "2206.07208", "version": "v1", "published": "2022-06-14T23:33:09.000Z", "updated": "2022-06-14T23:33:09.000Z", "title": "Partial Domination and Irredundance Numbers in Graphs", "authors": [ "Pawaton Kaemawichanurat", "Odile Favaron" ], "categories": [ "math.CO" ], "abstract": "A dominating set of a graph $G=(V,E)$ is a vertex set $D$ such that every vertex in $V(G) \\setminus D$ is adjacent to a vertex in $D$. The cardinality of a smallest dominating set of $D$ is called the domination number of $G$ and is denoted by $\\gamma(G)$. A vertex set $D$ is a $k$-isolating set of $G$ if $G - N_{G}[D]$ contains no $k$-cliques. The minimum cardinality of a $k$-isolating set of $G$ is called the $k$-isolation number of $G$ and is denoted by $\\iota_{k}(G)$. Clearly, $\\gamma(G) = \\iota_{1}(G)$. A vertex set $I$ is irredundant if, for every non-isolated vertex $v$ of $G[I]$, there exists a vertex $u$ in $V \\setminus I$ such that $N_{G}(u) \\cap I = \\{v\\}$. An irredundant set $I$ is maximal if the set $I \\cup \\{u\\}$ is no longer irredundant for any $u \\in V(G) \\setminus I$. The minimum cardinality of a maximal irredundant set is called the irredundance number of $G$ and is denoted by $ir(G)$. Allan and Laskar \\cite{AL1978} and Bollob\\'{a}s and Cockayne \\cite{BoCo1979} independently proved that $\\gamma(G) < 2ir(G)$, which can be written $\\iota_1(G) < 2ir(G)$, for any graph $G$. In this paper, for a graph $G$ with maximum degree $\\Delta$, we establish sharp upper bounds on $\\iota_{k}(G)$ in terms of $ir(G)$ for $\\Delta - 2 \\leq k \\leq \\Delta + 1$.", "revisions": [ { "version": "v1", "updated": "2022-06-14T23:33:09.000Z" } ], "analyses": { "keywords": [ "irredundance number", "partial domination", "vertex set", "minimum cardinality", "maximal irredundant set" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }